Ph.D. projects

Interactions of natural occurring microorganisms with uranium

Ph.D. student:

Ulrike Gerber

Supervisor:

Prof. Dr. Erika Kothe (FSU Jena), Prof. Dr. Thorsten Stumpf (HZDR)

Division:

Biogeochemistry

Period:

11/2013–10/2016

Uranium is a long-lived radionuclide that occurs naturally at high concentrations in some minerals. However it can also be disseminated in the environment as a consequence of mining activities or radioactive waste leaching. To understand the factors governing the bioavailability of uranium and ultimately its potential to incorporate into the food chain investigations are of a great importance.

The uranium waste mine Königstein (Saxony, Germany) is heavily polluted with heavy metals, especially with uranium. Despite the high concentrations of heavy metals, the mine is a reservoir for many different microorganisms that have evolved special strategies to survive in these extreme environments. Their ubiquitous occurrence is of fundamental interest to understand the migration behavior of radionuclides within the biosphere. Furthermore, microorganisms are the beginning of the food chain, and therefore the transfer of bound uranium along this food chain could rise to a serious threat to human health. Biosorption of radionuclides especially uranium by microorganisms regulates the mobility of the metal in the environment. Thus, microorganisms could be used to clean-up contaminated soils, sediments, and waters by removing uranium and other radionuclides, due to bioremediation processes.

The aim of this study should be to characterize the quantitative and structural interactions between different microorganisms and uranium in environmental concentrations and pH ranges.